It took me forever to find a shop that sells GL-4 gear oil. I found GL-5 gear oil at several shops. I guess this must be more common for cars. Apparently GL-4 and GL-5 are not compatible, or so says google. Anyways I did finally found the exact oil specified by the 1100's owners manual. They only sold it in this huge container though. Oh well, it should last me through several of my yearly gear oil changes.